21.   Pig intestines may regenerate damaged tissues.

22.   Casya has been under medical observation ever since and will likely need surgery to removed damaged tissue from his buttocks, Zaharia said.

23.   German team officials said later he would undergo surgery Friday afternoon in Berlin to remove damaged tissue and cartilage that had caused the right ankle to swell suddenly Thursday.

24.   He had surgery Sunday at Methodist to stabilize circulation and remove damaged tissue.

25.   He spent two hours in a recompression chamber to increase oxygen levels in his blood and help heal the damaged tissue, doctors said.

26.   In their attempt at repair, surgeons add their cancer-derived cells to the ring of damaged tissue that surrounds the dead area.

27.   Stem cells are found in embryos and umbilical cord blood and may one day be used to fight diseases such as diabetes and cancer by replacing damaged tissue.